Fix path to library files and change shebang line

'source' is a BASH keyword. Edit the path to the library files by
using the POSIX version of the 'source' keyword.

Also change the interpreter from #!/bin/bash to #!/bin/sh.

Reviewed-by: Amit Kucheria <amit.kucheria@linaro.org>
Signed-off-by: Lisa Nguyen <lisa.nguyen@linaro.org>
diff --git a/thermal/thermal_03.sh b/thermal/thermal_03.sh
index cf53a1a..a4504f5 100755
--- a/thermal/thermal_03.sh
+++ b/thermal/thermal_03.sh
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/bin/sh
 #
 # PM-QA validation test suite for the power management on Linux
 #
@@ -25,8 +25,8 @@
 
 # URL : https://wiki.linaro.org/WorkingGroups/PowerManagement/Resources/TestSuite/PmQaSpecification#thermal_03
 
-source ../include/functions.sh
-source ../include/thermal_functions.sh
+. ../include/functions.sh
+. ../include/thermal_functions.sh
 
 CPU_HEAT_BIN=../utils/heat_cpu
 cpu_pid=0